Objective: Superficial vein thrombosis may be complicated with venous thromboembolism. We examined factors predictive of venous thromboembolism in superficial vein thrombosis, which, to our knowledge, had not been prospectively studied before.
Design and methods: We performed post hoc analysis of the STENOX trial, a prospective randomized controlled trial that investigated various antithrombotic therapies in 427 hospitalized patients with objectively confirmed symptomatic isolated superficial vein thrombosis. The value of various baseline characteristics as predictive factors of venous thrombotic complications at 3 months was studied with logistic regression. Venous thrombotic complications were defined as deep vein thrombosis or pulmonary embolism, or recurrence or proximal extension of superficial vein thrombosis.
Results: Venous thrombotic complications occurred in 78 patients. Independent predictive factors for complications were superficial vein thrombosis of recent onset (odds ratio [OR], 3.01; 95% confidence interval [CI], 1.44-6.27), severe chronic venous insufficiency (OR, 2.75; CI, 1.10-6.89), male gender (OR, 2.17; CI, 1.28-3.68), and history of venous thromboembolism (OR, 2.07; CI 1.06-4.04). Deep vein thrombosis or pulmonary embolism occurred in 19 patients. Only severe chronic venous insufficiency was an independent predictor of this complication (OR, 4.50; CI, 1.30-15.61).
Conclusions: After symptomatic isolated superficial vein thrombosis, venous thrombotic complications are relatively frequent, and are more likely to occur in men, in patients with a history of venous thromboembolism or with severe chronic venous insufficiency, or in whom superficial vein thrombosis is recent. Knowledge of such predictive factors may be useful for determining appropriate treatment in patients with superficial vein thrombosis and for designing future phase III clinical trials.